a) Field of the Invention
The invention is directed to a process for the projection of images on a screen by means of a light bundle. The invention is further directed to a system with an individual projector for the display of an image on a screen by means of a light bundle, wherein the system can be used especially for carrying out the process according to the invention.
b) Description of the Related Art
Image projections have already been known for a very long time. Most notable in this respect is the Latema Magica from 1569 which is often referred to as the forerunner of modem slide projectors and episcopes. Film projectors, video projectors and head-up projectors should also be mentioned in this context.
With respect to video projectors, there are at present also other projectors, aside from eidophors and picture tube projectors, which project a video image on a screen in the manner of a slide or transparency, wherein the video image is electrically adjusted on an LCD matrix. Further, projectors are currently being developed in which a light bundle is directed onto a tilting mirror array, wherein the tilting mirror array generates the image content by rapidly switching individual tilting mirrors on and off based on locally different reflections of a light bundle which is then projected through an objective onto a screen. Modern developments, e.g., according to DE 43 42 849 C2, are also directed to the display of video pictures on a screen in that a laser beam is raster-scanned on a screen similar to an electron beam in an electron beam tube. The laser beam is color-modulated and intensity-modulated for the respective image points illuminated during scanning and a video image is made visible for an observer due to the rapid scanning and the inertia of the observer's eye.
Processes for the projection of images with these projection techniques are currently used in many commercial areas. The cinema is the best known example. Further, the proceedings at spectator events, political conventions and the like large-scale events are frequently made more visible for spectators at a distance by imaging speakers or artists by means of large-format video projection.
Further, projection methods of the type mentioned above are also used in advertising, particularly at trade fairs.
However, projection of the above-mentioned type creates problems especially in daylight. The light intensity is usually not sufficient in relation to sunlight, which can also strike the screen, for delivering adequately high contrast in order to view clear, high-quality images. Usually, no image at all can be detected when bright sunlight falls on the screen. However, it would be extremely desirable to be able to use the projection techniques mentioned above also in large open-air events, outdoor concerts, ball games or the like, so that spectators at a great distance from the proceedings, for example, at a ball game, can also clearly discern details on a large screen so as to make attendance at the event more appealing to these spectators and dissuade them from the alternative of viewing the televised event.